Positive CAR(Chemically Amplified Resist) is exposed by electron beam and PAGs(Photo Acid Generator) of
photoresist release acids. Protecting groups of exposed polymers are de-protected by the acids and unexposed polymers
still keep having protecting groups. It brings out dissolution difference between exposed and unexposed photoresist in
develop process. Unexposed photoresist should be remained after develop process as much as needed for patterning.
However, we have observed that unexposed photoresist also can be dissolved by developer droplet with hundreds
micrometer size. It resulted in photoresist pinholes after develop process and clear defects after dry etching and
Firstly, we have studied the pinhole defect formation mechanism by verifying the difference between normal develop
process and developer droplet. It was confirmed that the dissolution difference are caused by phase environment
difference, 2 phases(solid - liquid) for normal develop process and 3 phases(solid - liquid - air) at meniscus boundary
for developer droplet. It also can be explained on different dissolution rate by droplet size.
Also, possible defect types by developer droplet have been reviewed through process simulation to narrow down the
critical steps in develop process. Besides, some of easy accessible process parameters have been evaluated to see
whether they are effective or not for clear defect reduction.
As integration of circuits increases, required feature size becomes smaller and smaller. Defect control becomes tighter
due to decrease in defect size that affects the images printed on the wafer and increase in possibility to be killer defect
like 2-face bridge defect. Therefore, particle sources from all processes should be controlled extremely.
Especially for dry etching process, Alumina ceramic has been widely used for plasma resistance material such as
electrode covering plate and insulator. However, they can be etched under 'F' series plasma condition as well, even in
small amounts. It has been reported that non-volatile by-products from etch ceramic can be particle sources to be killer
defect. Therefore, selection of ceramic materials must be important for particle control in dry etch process.
This paper pertains to testing etch resistance differences in Alumina (Al<sub>2</sub>O<sub>3</sub>) and Yttria (Y<sub>2</sub>O<sub>3</sub>) ceramic materials
depending on various density and surface roughness. Ceramic surface microstructures change after plasma treatment was
observed with scanning electron microscope (SEM) and ceramic erosion rate after plasma treatment was measured with
In previous study, it has been reported that photo resist erosion after development gets severe as patterns size decreases.
The 60nm feature requiring for SRAF(Sub Resolution Assistant Feature) of 45nm technology node, the photo resist
erosion after develop on unexposed area was almost 400Å. It will be a serious problem to degrade not only the resist
thickness margin for thinner resist to enhance resolution and pattern collapse, but also CD(Critical Dimension)
performance capability such as CD linearity and SRAF resolution capability by proceeding dry etching.
In this paper, the effects of photo resist erosion by pattern size on CD linearity performance were studied. The photo
resist erosion by pattern size was simulated with the Gaussian blur model before dry etching. The effects of dosage,
PEB(Post Exposure Bake) temperature and development conditions were evaluated to reduce blur value before dry
As the industry approaches to 45nm and below lithography, resolution and pattern collapse of SRAF (Sub Resolution
Assistant Feature) on photoresist is becoming critical issues on photomask industry. The collapse of photoresist pattern
has been become a serious problem in manufacturing of fine patterns in wafer and mask industries. The presumed causes
of the resist pattern collapse are capillary forces acting on the patterns and adhesion property of the patterns. The use of
thinner resist thickness has been known as one of the most effective method among reported literatures. However,
etching resistance of present resist is still bad. Therefore it is difficult to reduce the photoresist thickness, though the
pattern size is very small.
In this paper, the available limits of resist thickness for FEP171 were calculated for several kinds of common absorber
layers as considering current dry etch capability. We focused on pattern design and collapse window for SRAF. FEP171
resist performance especially for resolution and collapse window were evaluated for both 2000Å and 3000Å thickness
with line, space, and length focused on sub 100nm features. Radial position effect and drying conditions were studied