• 반도체디스플레이기술학회지
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• 제9권3호
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• pp.47-51
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• 2010

This paper presents a wafer pre-alignment system which is improved using the image of the entire wafer area. In the previous method, image acquisition for wafer takes about 80% of total pre-alignment time. The proposed system uses only one image of entire wafer area via a high-resolution CMOS camera, and so image acquisition accounts for nearly 1% of total process time. The larger FOV(field of view) to use the image of the entire wafer area worsen camera lens distortion. A camera calibration using high order polynomials is used for accurate lens distortion correction. And template matching is used to find a correct notch's position. The performance of the proposed system was demonstrated by experiments of wafer center alignment and notch alignment.

• 반도체디스플레이기술학회지
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• 제9권1호
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• pp.11-16
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• 2010

Wafer Pre-Alignment is to find the center and the orientation of a wafer and to move the wafer to the desired position and orientation. In this paper, an area camera based pre-aligning method is presented that captures 8 wafer images regularly during 360 degrees rotation. From the images, wafer edge positions are extracted and used to estimate the wafer's center and orientation using least squares circle fitting. These data are utilized for the proper alignment of the wafer. For accurate alignments, camera calibration methods using high order polynomials are used for converting pixel coordinates into real-world coordinates. A complete pre-alignment system was constructed using mechanical and optical components and tested. Experimental results show that alignment of wafer center and orientation can be done with the standard deviation of 0.002 mm and 0.028 degree, respectively.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2009년도 추계학술대회
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• pp.410-413
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• 2009

웨이퍼 Pre-Alignment는 반도체 공정에서 장비에 웨이퍼를 놓기 전에 웨이퍼의 중심 및 방향을 정확하게 정렬할 필요가 있는데, 이를 위해서 일정한 수준 이하로 중심과 방향을 찾아 Alignment 하는 방법을 말한다. 본 논문에서는 웨이퍼를 Alignment 하기 위해 기존의 Mechanical한 방법이 아닌 Area 카메라를 통한 비접촉식 방법을 이용하였다. 이 방법은 웨이퍼를 45도씩 8번씩, 한 바퀴를 회전하여 이미지를 획득한 뒤, 이미지의 웨이퍼의 에지값 들을 이용하여 Least Square Circle Fitting을 이용하여 웨이퍼의 중심과 방향을 정확하게 측정하여 Alignment를 한다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.203.1-203.1
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• 2016

Poly etch 설비에서 발생하는 dechuck 불량에 의한 Dynamic Alignment(DA) error는 poly etch 설비에서의 고질 적인 문제이다. 발생 원인은 ElectroStatic Chuck(ESC)의 노후화 혹은process plasma에 의한 attack 등으로 ESC와 wafer간 dechucking이 진행될 때 wafer내의 전하가 완전히 discharge되지 못하여 wafer Sticking에 의한 sliding이 발생되며 심해지면 Dynamic Alignment(DA) Error가 발생한다. DA error 발생 되면 particle down으로 wafer는 scrap 되며 DA error가 지속적으로 발생하는 설비는 ESC 교체를 하고 있다. ESC 교체비용도 매우 크며 교체 전까지 설비가 멈추어있는 시간적인 손실이 발생하게 된다. Dechucking을 진행할 때 Wafer에 잔존하는 전하를 제거 하여 Wafer의 sticking을 줄여 DA error를 근원적으로 방지하기 위해 plasma를 이용하여 wafer와 ESC를 하나의 electric circuit으로 연결시키는 방법으로 wafer에 잔존하는 전하를 제거 시키고자 하였다.

• 한국정밀공학회지
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• 제11권1호
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• pp.150-156
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• 1994

To meet the process requirement of semiconductor device manufacturing, it is necessary to improve the alignment accuracy in exposure equipments. We developed the excimer laser stepper and will describe the methodology for alignment measurement and experimental results. Our wafer alignment system consists of off-axis optics, TTL(Through The Lens) optics and high precision stage. Off-axis alignment utilizes the image processing and /or diffraction from thealign marks of off-centered chip area. On the other hand, TTL alignment can be used for the die-by-die alignment using dual beam interferometry. When only off-axis alignment was used, the experimental alignment error(lml+3 .sigma. ) was 0.26-0.29 .mu. m, and will be reduced down to 0.15 .mu. m by adding TTL alignment.

• 제어로봇시스템학회논문지
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• 제8권9호
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• pp.812-817
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• 2002

This paper presents a development of high accuracy aligner and describes a method to find the orientation of a substantially circular disk shaped wafer with at least one flat region on an edge thereof. In the developed system, the wafer is spun one 360 degree turn on a chuck and the edge position is measured by a linear array to obtain a set of data points at various wafer orientation. The rotation axis may differ from wafer center by an unknown eccentricity. The flat angle is found by fitting a cosine curve to the actual data to obtain a deviation. The maximum deviation is then corrected for errors due to a finite number of data points and wafer eccentricity by calculating an adjustment angle from data points on the wafer fiat. After determining the flat angle the wafer is spun to the desired orientation. The wafer eccentricity can be calculated from four of the data points located away from the flat edge region. and the wafer is then centered.

• 한국정밀공학회지
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• 제20권12호
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• pp.105-114
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• 2003

In this study, a dicing machine with vision system was built and an algorithm for automatic alignment was developed for dual camera system. The system had a macro and a micro inspection tool. The algorithm was formulated from geometric relations. When a wafer was put on the cutting stage within certain range, it was inspected by vision system and compared with a standard pattern. The difference between the patterns was analyzed and evaluated. Then, the stage was moved by x, y, $\theta$ axes to compensate these differences. The amount of compensation was calculated from the result of the vision inspection through the automatic alignment algorithm. The stage was moved to the compensated position and was inspected by vision for checking its result again. Accuracy and validity of the algorithm was discussed from these data.

• 반도체디스플레이기술학회지
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• 제21권1호
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• pp.142-147
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• 2022

After introducing Hybrid Bonding technology into image sensors using stacked sensors and image processors, large quantity production became possible. As a result, it is currently used in most of the CMOS image market in smartphones and other image-based devices worldwide, and almost all stacked CIS manufacturing sites have focused on miniaturization using hybrid bonding. In this study, an upper wafer handling module for Wafer to Wafer Hybrid Bonding developed to increase the alignment and precision between wafers when wafer bonding. The module was divided two parts to reduce error of both the alignment and degree of precision during wafer bonding. Wafer handling module developed both new Tip/Tilt system controlling θx,θy of upper wafer and striker to push upper wafer. Based on this, it was confirmed through the stability evaluation that the upper wafer handling module can be controlled without any problem during W2W hybrid bonding.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1993년도 추계학술대회 논문집
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• pp.243-248
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• 1993

New methodology for fiducial alignment is proposed to improve the alignment accuracy in wafer steppers. The positioning error is detected by PSD(Position Sensitive Detector)when 2-dimensional vernier patterns on a reticle on a reticle are projected on the fiducial marks of wafer stage. The width and period of vernier patterns are deter mined to get the highest S/N ratio for the exposure wavelength 248.4nm of KrF excimer laser. This new method has an advantage of higher accuracy and faster alignment over the conventional one.

• 한국광학회지
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• 제4권1호
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• pp.15-21
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• 1993

본 연구에서는 설계제작된 KrF 엑시머 레이저 스텝퍼는 광원인 KrF엑시머 레이저, 조명광학계, 축소트영광학계, 정밀구동 웨이퍼 스테이지, 정렬시스템 및 이들을 제어하기 위한 제어계로 구성되어 있다. 본 실험에서 사용한 KrFdprtlaj 레이저는 밴드폭 3pm, 반복주파수 200Hz, 평균축력 3W이고, 5:1 투영렌즈는 N.A. 0.42, 전체 필드영역 $\varphi$21.2mm, 왜곡수차 최대 60nm 이하이다. 또한 정밀구동 웨이퍼 스테이지의 재현성과 해상도는 각각 $\pm$0.08$\mu\textrm{m}$/200mm(3 sigma), 100mm 반경에서 0.05 $\mu\textrm{m}$이다. 자동 초점 시스템은 $\pm$50$\mu\textrm{m}$범위에서 0.1$\mu\textrm{m}$의 해상도를 나타냈으며, 자동수평시스템은 120 arcsec 범위에서 larcsec의 해상도를 나타냈다. OFF-AXIS 정렬방식에서는 0.2$\mu\textrm{m}$의 해상도를 가지며, 두빔의 간섭을 이용한 새로운 TTL 정렬은 0.1$\mu\textrm{m}$의 해상도를 나타냈다. 스텝퍼 패턴 실험결과 SAL603레지스트를 사용하였을 때 웨이퍼의 노광후 열처리 $105^{\circ}C$, 60초에서 0.3$\mu\textrm{m}$ Lines and Spaces(L/S)까지 해상되었으며, 0.34$\mu\textrm{m}$ L/S에서 1$\mu\textrm{m}$의 초점심도를 얻을 수 있었다. 마스크 패턴과 레지스트 패턴의 선형성은 0.4$\mu\textrm{m}$ L/S가지 유지 되었다. 또한 XP-89131레지스트의 경우 노광후 열처리 $110^{\circ}C$, 60초에서 0.34$\mu\textrm{m}$ L/S까지 해상됨을 알수 있었다.