New Product: Haze Removal System PROMAHAZE

KrF or ArF lasers of short wavelengths are widely used as lithography light sources for transferring circuit patterns on photmask onto wafer surface in response to the fact that the design rule of semiconductor devices becomes finer and finer. Photon energy of ArF laser used specifically for most advanced devices is extremely high and induces chemical reaction of substances adsorbed to the photomask surface, which leads to generation of solid state foreign substance with growth potential (generally called "Haze") on the photomask surface.
Because the size and the quantity of haze increases generally with time lapse and repetition of exposure, a situation in which incorrect patterns are transferred onto wafer and subsequently defective devices are produced occurs if any measures were not taken against this kind of haze problem. Thus far, a lot of work and cost have been pumped into counter measures against this haze issue. Currently, in many semiconductor device makers (wafer fabs), regular particle inspection and monitoring of haze generation status are performed to prevent yield deterioration originating to bad effects of haze.
When haze grows to such a level as to influence device performance, the haze-contaminated masks need to go through the following procedure "(1) dismounting of pellicle frame, (2) wet cleaning of mask, (3) re-mounting of pellicle, (4) particle inspection". In general, wafer fabs need to have the photomask with haze problems go through this sequential procedure by sending the photomask to a maskshop that has specific equipments for this sequential procedure.
Currently, the issue of counter measures against haze has emerged as one of the most important items for device makers including necessitated preparation of backup photomasks.
The Haze Removal System "PROMAHAZE" presented here by Lasertec is an innovative new tool that solves the haze problem at wafer fabs as mentioned above. This system with an entirely new concept quickly and easily removes the effect of haze, drastically cutbacks the cost for repeated photomask wet cleaning at maskshops and contributes to more efficient production of semiconductor devices as a result.
The Haze Removal System "PROMAHAZE" utilizes, in principle, irradiation of light on photomasks, which removes haze as a result of decomposition of haze at photomask surface into gaseous substances. Both ammonium sulfate type haze and organic material type haze are effectively removed. Also a function that replaces residual contaminated gas in the space of pellicle frame with clean air is equipped, which restrains renewed haze growth after haze removal. Operation time of the system is short and this system realizes drastic reduction of photomask related cost at wafer fabs.
Furthermore, total photomask management at wafer fabs becomes possible by coordinated operation of the haze removal system PROMAHAZE with the photomask inspection system MATRICS and the phase shift/transmittance measurement system MPM193EX.

• Enable haze cleaning of photomasks with pellicle attached
• Substitute air inside the pellicle frame with chemically clean air
• High-throughput haze cleaning by high-speed irradiation over the whole photomask area
• Local haze cleaning by spot irradiation
• Haze image review function based on a defect coordinate file and high resolution optics

• Removal of haze on photomasks at wafer fabs
• Total photomask management at wafer fabs including verification of haze generation situation and confirmation of photomask status after haze removal in addition to measurement and confirmation of phase shift/transmittance, by coordinated operation of the haze removal system PROMAHAZE with the photomask inspection system MATRICS and the phase shift/transmittance measurement system MPM193EX.