• Journal of the Korean Society for Industrial and Applied Mathematics
• /
• 제10권1호
• /
• pp.1-9
• /
• 2006

Photomask 고해상도 검사기를 개발함에 있어서 기계 설계, 제어 설계, 소프트웨어 설계 등 3개의 카테고리가 필요하다. 그 중에서 소프트웨어 설계는 CAD 데이터와 Photomask로부터 카메라로 읽어 들인 실제 영상과의 비교를 통하여 불량을 검출한다. 픽셀 단위로 비교하기 때문에 전체 영역이 커서 블록으로 나누어서 비교하는 블록 매칭 알고리즘을 사용한다. 그리고 기계 조립 정도에서 오는 오차를 보정하기 위하여 Calibration 알고리즘을 쓰고, Photomask의 곡면을 보정하기 위하여 카메라 사전 초점 알고리즘을 제시한다.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2008년도 하계종합학술대회
• /
• pp.933-934
• /
• 2008

This paper describes the process of extracting defect from optical photomask images. We introduce a new method of finding photomask detects with a single optical photomask damaged image. The proposed algorithm is efficient when an original undamaged image is unavailable. The experiment showed that even a small and discontinuous photomask defect was extracted as well as continuous type of defects.

• ETRI Journal
• /
• 제27권2호
• /
• pp.188-194
• /
• 2005

We report on the improvement of critical dimension (CD) linearity on a photomask by applying the concept of process proximity correction to a laser lithographic process used for the fabrication of photomasks. Rule-based laser process proximity correction (LPC) was performed using an automated optical proximity correction tool and we obtained dramatic improvement of CD linearity on a photomask. A study on model-based LPC was executed using a two-Gaussian kernel function and we extracted model parameters for the laser lithographic process by fitting the model-predicted CD linearity data with measured ones. Model-predicted bias values of isolated space (I/S), arrayed contact (A/C) and isolated contact (I/C) were in good agreement with those obtained by the nonlinear curve-fitting method used for the rule-based LPC.

• 센서학회지
• /
• 제32권5호
• /
• pp.280-284
• /
• 2023

In this study, a prototype micro-scale photomask and microfluidic channel mold were fabricated using the thermal shrinkage of the polymer. A polystyrene (PS) sheet was used as the heat-shrink polymer, and the patterns of the photomask and microchannel are interdigitated electrodes. Patterns were formed on the PS sheets using a commercial laser printer. The contraction ratio of the PS sheet was approximately 60% at a temperature of 150 ℃, and the transmittance was reduced by approximately 0% at a wavelength of 365 nm. The microfluidic channel had a round shape. The proposed technique is simple, facile, and inexpensive for fabricating a micro-scale photomask and microfluidic channel mold and does not involve the use of any harmful materials. Thus, this technique is well-suited for fabricating diverse micro-scale patterns and channels for prototype devices, including sensors.

• 한국광학회지
• /
• 제18권1호
• /
• pp.74-78
• /
• 2007

본 논문에서는 포토마스크 후면에 위상 패턴을 형성하여 웨이퍼 상 CD(critical dimension) 균일도를 개선할 수 있는 투과율 조절 포토마스크 기술을 ArF 리소그래피에 적용한 결과에 대하여 보고한다. 위상 패턴 조밀도에 따른 노광 광세기 변화 계산에 포토마스크 후면으로부터 포토마스크 전면까지의 광의 전파를 고려하여 ArF 파장에서의 위상 패턴 조밀도에 따른 노광 광세기 저하에 관한 실험결과를 이론적으로 재현할 수 있었다. 본 기술을 ArF 리소그래피에 적용하여 DRAM(Dynamic Random Access Memory)의 한 주요 레이어에 대해 필드 내 CD 균일도를 $3{\sigma}$ 값으로 13.8 nm에서 9.7 nm로 개선하였다.

• 한국전기전자재료학회논문지
• /
• 제17권7호
• /
• pp.697-700
• /
• 2004

We propose a method that realizes the modified illumination by implementing a binary phase grating at the backside of a photomask. By modeling the relationship between the shape of a grating on the photomask and the light intensity at the pupil plane, we developed a program named MIDAS that finds the optimum grating pattern with a stochastic approach. After applying the program to several examples, we found that the program finds the grating pattern for the modified illumination that we want. By applying the grating at the backside of a photomask, the light efficiency of modified illumination may be improved.

• 한국광학회지
• /
• 제15권1호
• /
• pp.79-85
• /
• 2004

후면의 석영면에 위상 패턴을 형성하여 투과율 조절을 구현한 포토마스크에 대해 보고한다. 위상 패턴의 크기와 패턴 조밀도에 따른 조명 동공의 형태 변화에 관한 이론적 결과와 투과율 조절 포토마스크를 사용한 웨이퍼 상 CD(critical dimension) 균일도 개선에 관한 실험적 결과에 대해 기술한다. 투과율 조절을 위한 위상 패턴은 패턴이 형성되지 않은 영역에 대해 180$^{\circ}$의 상대적 위상을 갖도록 석영면을 식각한 콘택홀 형태의 패턴을 사용하였다. 콘택홀 패턴의 크기가 작을수록 본래의 조명동공 형태를 유지하게 되며, 동일한 패턴 조밀도에서 더욱 큰 노광 광세기 저하가 일어남을 알 수 있었다. 패턴 조밀도를 위치별로 변화시켜 CD균일도 개선에 적합한 투과율 분포를 포토마스크 후면에 형성하였다. 투과율 조절 포토마스크를 140nm 디자인 롤을 갖고 있는 DRAM(Dynamic Random Access Memory)의 한 주요 레이어에 적용하여 CD 균일도를 3$\sigma$값으로 24.0nm에서 10.7nm 로 개선할 수 있었다.

• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
• /
• pp.520-523
• /
• 2009

The drive towards lowering costs and increasing frame rates results in new panel designs and thereby new photomasks designs. One common way to reduce cost is to reduce the number of production steps. For this multi tone photomasks (MTM) are needed. MTMs contain more information and increases photomask placement requirements. Increasing frame rates lead to shrinking geometries. The combination of HTM and shrinking geometries drastically increases the requirements imposed on the pattern generators used to print the photomasks. New methods are therefore needed to enable future photomask manufacturing. This paper introduces three advanced image quality enhancing methods.

• 한국표면공학회지
• /
• 제55권6호
• /
• pp.353-362
• /
• 2022

Recently, transmittance of photomasks for ultra-violet (UV) region is getting more important, as the light source wavelength of an exposure process is shortened due to the demand for technologies about high integration and miniaturization of devices. Meanwhile, such problems can occur as damages or the reduction of yield of photomask as electrostatic damage (ESD) occurs in the weak parts due to the accumulation of static electricity and the electric charge on chromium metal layers which are light shielding layers, caused by the repeated contacts and the peeling off between the photomask and the substrate during the exposure process. Accordingly, there have been studies to improve transmittance and antistatic performance through various functional coatings on the photomask surface. In the present study, we manufactured antireflection films of Nb₂O₅, | SiO₂ structure and antistatic films of ITO designed on 100 × 100 × 3 mmt sodalime glass by DC magnetron sputtering system so that photomask can maintain high transmittance at I-line (365 nm). ITO thin film deposited using In/Sn (10 wt.%) on sodalime glass was optimized to be 10 nm-thick, 3.0 × 103 𝛺/☐ sheet resistance, and about 80% transmittance, which was relatively low transmittance because of the absorption properties of ITO thin film. High average transmittance of 91.45% was obtained from a double side antireflection and antistatic thin films structure of Nb₂O₅ 64 nm | SiO₂ 41 nm | sodalime glass | ITO 10 nm | Nb₂O₅ 64 nm | SiO₂ 41 nm.

• 한국표면공학회지
• /
• 제28권2호
• /
• pp.101-109
• /
• 1995

Electroetching rates of $FeCl_3$ solution were increased according to increasing solution temperature. Activation energy of electroetching at Be'36 and 5A/$dm^2$ condition was 28.3Kcal and also, at Be'46 and 5A/dm$^2$ condition was 33.2Kcal. At Be'36 concentration of $FeCl_3$ solution, electroetching rate were more higher than at Be'46 concentration. Surfaces of etched grooves obtained at 8A/$dm^2$ or higher current density in 46 Be' concentration of $FeCl_3$ solution were observed to be flat and smooth owing to suppressing chemical etching reaction. Distinctly etched boundaries became to be appeared at 2A/$dm^2$ in Be'41 electroetching condition by differential effects. In case of applying 8A/$dm^2$ current density to Be'46 of $FeCl_3$ solution, etching depth were 4 times and side etching were 6 times more than chemical etching case respectively.