Si TFT공정과 포토리소그래피 공정 조사 레포트

소개

성균관대 디스플레이 재료실험 과목
Si을 이용한 TFT공정과 포토리소 그래피 공정을 조사한 레포트입니다.

목차

1. Si-TFT manufacturing
1) What is TFT?
2) Manufacturing a-Si TFT
3)
2. Photolithography
1) Wafer Cleaning, Barrier Formation and Photoresist Application
2) Positive and Negative Photoresist
3) Soft-Baking
4) Mask Alignment and Exposure
5) Contact Printing
6) Proximity Printing
7) Projection Printing
8) Development
9) Hard-baking

본문내용

STN is this type. STN is used to display many things. TN is used for clock and calculator.
Active matrix (TFT-LCD)
Transistor works as switch for coordinating electrical voltage. It controls pixels independently. So it hasn’t “Crosstalk” by line interference and it can display more clearly. These days this type is used for LCD monitor, laptop PC.
TFT-LCD structure
TFT-LCD (Thin Film Transistor Liquid Crystal Display) has a sandwich-like structure with liquid crystal filled between two glass plates.
tor fabrication. While a Color Filter Glass has color filter which generates color. Liquid crystals move according to the difference in voltage between the Color Filter Glass and the TFT Glass. The amount of light supplied by Back Light is determined by the amount of movement of the liquid crystals in such a way as to generate color.
Structure of TFT
This picture is structure of a-Si TFT (a-Si TFT is generally used in TFT-LCD)
And the gate is located under source and drain that is called inverse stagger type. This type is used in most cases.
Role of TFT
lied voltage to LCD Panel, liquid crystal is arranged to electric field. Input light is absorbed by backside polarizer and if we didn’t




Proximity Printing
The proximity exposure method is similar to contact printing except that a small gap, 10 to 25 microns wide, is maintained between the wafer and the mask during exposure. This gap minimizes (but may not eliminate) mask damage. Approximately 2- to 4-micron resolution is possible with proximity printing.
Projection Printing
ieve high resolution, only a small portion of the mask is imaged. This small image field is scanned or stepped over the surface of the wafer. Projection printers that step the mask image over the wafer surface are called step-and-repeat systems. Step-and-repeat projection printers are capable of approximately 1-micron resolution.
Development
One of the last steps in the photolithographic process is development. The figure below shows response curves for negative and positive resist after exposure and development.
all the resist processing variables: initial resist thickness, prebake conditions, developer chemistry, developing time, and others.
Hard-baking

참고자료

· Lecture Note “Photolithography”, 조동일, 서울대 전자공학과
· color filter 공정 및 장비업체 소개, www.displaybank.com
· http://www.ece.gatech.edu/research/labs/vc/theory/photolith.html
· http://blog.daum.net/hyun2760/2638534?srchid=BR1http%3A%2F%2Fblog.daum.net%2Fhyun2760%2F2638534
· pid=fqm8lg331xCsstuJ5q0ssv--
· logNo=50013198986
· logNo=80002229728
· http://www.hdtv.ca/plasma_lcd_projector/images/How_TFT-LCD_Pixels_Work_2.jpg
· http://www.lgdisplay.com/homeContain/jsp/kor/tech/tech210_j_k.jsp LG디스플레이 기술정보 TFT-LCD 공정부분
· http://en.wikipedia.org/wiki/Photolithography